U.S. Pat. No. 6,163,098 to Taylor et al. and U.S. Pat. No. 4,789,801 to Lee describe various devices to generate a stream of ionized air using so-called electro-kinetic techniques. In some applications, the electro-kinetic devices may be small enough to be handheld, and in other applications electro-kinetic devices may be large enough to condition the air in a room. In overview, electro-kinetic techniques use high electric fields to ionize air molecules, a process that produces ozone (O3) as a byproduct. Ozone is an unstable molecule of oxygen that is commonly produced as a byproduct of high voltage arcing. In safe concentrations, ozone can be a desirable and useful substance. But ozone by itself may not be effective to kill microorganisms such as germs, bacteria, and viruses in the environment surrounding the device.
FIG. 1 depicts a generic electro-kinetic device 10 to generate ozone. Device 10 includes a housing 20 that typically has at least one air input port 30 and at least one air output port 40. Within housing 20 there is disposed an electrode assembly or system 50 comprising a first electrode array 60 having at least one electrode 70 and comprising a second electrode array 80 having at least one electrode 90. System 10 further includes a high voltage generator 100 coupled between the first and second electrode arrays. Electrodes 70 and electrodes 90 may have a variety of shapes. For example, electrodes 70 may be thin electrical wires, and electrodes 90 may be larger wires, rods, or other shapes. Electrodes 70 may be pointed or pin-like, and electrodes 90 may be curvilinear, including ring shaped, or may comprise a conductive plate with curved or ring-like openings formed in the plate. Electrodes 90 typically are symmetrically disposed relative to electrodes 70. For example, if there are three electrodes 70 in first electrode array 60, there might be two electrodes 90 in second electrode array 80, wherein electrodes 90 are staggered to be equidistant from the nearest electrodes 70. In the pin and ring type configurations, electrodes 90 are preferably concentric with electrodes 70.
In the various configurations, all of the electrodes are electrically conductive material, metal for example Electrodes 90 preferably have a larger radius than electrodes 70, with the result that a large electric field is created at or adjacent electrodes 90 upon application of high voltage (typically several kV) from generator 100. As a result ozone and ionized particles of air are generated within device 10, and there is an electro-kinetic flow of air in the direction from the first electrode array 60 towards the second electrode array 80. In FIG. 1, the large arrow denoted IN represents ambient air that can enter input port 30. The small “x's” denote particulate matter that may be present in the incoming ambient air. The air movement is in the direction of the large arrows, and the output airflow, denoted OUT, exits device 10 via port 40. An advantage of electro-kinetic devices such as device 10 is that an air flow is created without using fans or other moving parts to create the air flow.
Preferably particulate matter x in the ambient air can be electrostatically attracted to the second electrode array 80, with the result that the outflow (OUT) of air from device 10 not only contains ozone and ionized air, but can be cleaner than the ambient air. In such devices, it can become necessary to occasionally clean the second electrode array electrodes 80 to remove particulate matter and other debris from the surface of electrodes 90. Thus, device 10 in FIG. 1 can function somewhat as a fan to create an output air flow, but without requiring moving parts. Ideally the outflow of air (OUT) is conditioned in that particulate matter is removed and the outflow includes safe amounts of ozone, and some ions.
But an outflow of air containing ions and ozone may not destroy or reduce microorganisms such as germs, bacteria, fuingi, viruses, and the like, collectively hereinafter “microorganisms”. It is known in the art to try to destroy such microorganisms with so-called germicidal lamps. Such lamps emit ultra violet radiation having a wavelength of about 254 nm. For example, devices to condition air using mechanical fans, HEPA filters, and germicidal lamps are sold commercially by companies such as Austin Air, C.A.R.E. 2000, Amaircare, and others. Often the devices are somewhat cumbersome, and have size and bulk of a small filing cabinet. In such devices, care must be taken to ensure that ultraviolet radiation from the germicidal lamp cannot be viewed by nearby persons, to prevent eye injury. Although such fan-powered devices can reduce or destroy microorganisms, the devices tend to be bulky, and are not necessarily silent in operation.
What is needed is a device to condition air in a room that can operate relatively silently to remove particulate matter in the air, that can preferably output safe amounts of ozone, and that can also kill or reduce microorganisms such as germs, fungi, bacteria, viruses, and the like.
The present invention provides such a device.